Billy...I have to agree with AD-52. Without backpressure no engine runs as well as it will with some. If your running a split or dual exhaust manifold keep your exhaust to 1.75 into the muffler. Dual 1.75 or 2" outlets work OK on a one-in two-out muffler. IMO 2.25" is quite large for most Chevy inlines. Why don't you check out Flowmaster and/or Gibson websites and see what they have to say about it.
Bigger isn't always better.
